1. The Triumph TT600 shock absorber has the same overall eye to eye length as the OEM XZ400/XZ550 shock absorber. 315mm.2. The top eye does not fit directly into the existing securing point without chopping in to the frame. To avoid this Glynn Pickering has created an adapter plate and I have followed his example. This allows the frame and shock to be returned to original if required in the future but, since the original shock is regarded as useless, why would you?

Top Adaptor and Bush

3. My top adapter is made up of 5mm steel. I have placed the securing points on the same 315mm arc to try to keep the ride characteristics as close as I could to the original. To create the top adapter plate, I used 3 steel components cut out on a waterjet cutter and then welded. The component plans are made with Google Sketch-Up and can be converted to .dxf files for cutting.I used the original bolt to secure the adapter plate into the frame, and then used a 12mm bolt in the top hole to secure the shock absorber. The top eye of the shock absorber is mild steel and can be drilled or reamed to suit the bolt ensuring a snug fit. (Alternatively, use the original TT600 bolt size if you got a bolt with your shocker but adjust my plans using SketchUp to suit your bolt diameter)

Before committing to manufacture, ensure you double check all my measurements against your setup in case there are differences between my frame/shock absorber and yours.

4. The base of the adapter plate in my plans needs to be hand filed into a slightly trapezoid shape so that it slips snugly into the base of the original mounting on your frame. It will probably need about 0.75mm off each side of the ¼ round front edge, tapering out towards the rear.

5. The width of the top eye of the TT600 shocker is 30mm. I had a piece of galvanised pipe, about 25mm in diameter, cut to this exact length. Place this 30mm temporary spacer tube between the two upright plates and secure with your top bolt. Place in your frame on top of the newly fitted base plate and check the alignment of the lower securing bolt holes with the original frame bolt holes. Adjust if necessary by grinding and tweaking the base. When complete, mark up the base plate and the upright plates for welding together. Leave the spacer tube bolted in during welding to help with alignment. To get better weld penetration, make sure that each weld face on the vertical plates has a decent chamfer.

After welding, double check for fitting and clearances before painting or powder coating. The TT600 shock top fitting should fit snugly between to two upright plates of the adapter

Bottom Bush

6. The TT600 shocker has a 10mm sleeve in the lower needle bearing race. Using a little wire wool on your original 10mm securing pin to remove any rust, this should slip firmly into the shock absorber sleeve. However, as POD points out, there is a risk of the sleeve “wandering” on this lower securing pin because the TT600 shock has a roller bearing and sleeve. I have used 10mm ID thrust washers either side of the lower mounting to reduce sideways play. I found that two hardened steel washers, each with a thickness of 2.8mm took up the slack perfectly. You may want to replace the needle race with a neoprene fitting and bush as suggested by POD.

One of the disadvantages of my setup is that the roller bearing will be exposed to dust, salt and water and may eventually need replacing. But I will probably be dead by then. Alternatively, follow POD's suggestion and have the roller bearing replaced with a urethane fitting and a suitably sized bush at your local shock shop.Initial Shock settings

7. My TT600 shock has three adjustments, Spring tension (preload),Rebound Dampening (at bottom of shock) and Compression Dampening(on reservoir). As a guide I have used this chart to setup my preliminary settings: My shock came off an '02 Triumph TT600. 35mm of thread showing above the spring, and 3 clicks out on the rebound dampening and 7 clicks out on the compression dampening. (Don’t count the first click from screwed right in.) The bottom rebound dampening screw can be accessed through the access plug behind the ECU unit.

Below are jpegs of the adapter components to be made from 5mm steel. Email me at johnmalcolmATfastmail.fm if you would like the original Google Sketchup files. An extension to Sketchup enables the .skp format to be converted to .dxf or .stl files for waterjet cutting.

Photos and testing to follow... The wet weight of the TT600 is 413lb compared with 467lb of the XZ550. I am hoping the difference will not be significant.

Although I am chuffed about how the conversion has worked out so far, I am not so happy about the movement in my swing arm when I push and pull on the back wheel after replacing the roller bearings. PITA. Can you detect any movement in your swing arm?

I replaces the bearings in mine ,,,and it wasn't any better,,pinhole come up with a fix for us

IainNZ

Yeah, I replaced the swingarm bearings too. Still, there's an unhealthy amount of movement there. It's not like the axle is all sloppy - it seemed a tight fit when the swingarm's not attached. Two theories:1. Tiny amounts of slop make a big difference at the far end of the swingarm2. The entire frame is flexing

Well, I am relieved that others are finding movement. I had a pedantic engineer friend come and have a look. I was able to show him the slop in the hardened sleeve when the swing arm bolt was through it, (out of the xz400 spares machine). He reckoned that 0.02mm slop would account for that movement at the rear of the wheel. Felt a bit cheated though having pressed new bearings in and expecting a miracle.

But if Iain can out-corner his Ducati friends with a self steering swing arm on the XZ550, that is good enough for me!.

The only solution I reckon would be to dispense with roller bearings, press in bronze and then ream them out to suit a new (hardened?) swing arm bolt. But unless you line bored through the frame, the two bronze bearings would only have the same length as the roller bearings which might not be enough surface area to deal with the torque and twist.

I have been following this thread for a while and, out of curiosity, I finally went out and checked my low mileage '83. I had the pivot apart and lubed with the waterproof grease I had available. So, after 13 years and maybe 4K miles, I have zero play in the pivot but when I apply side force to the top of the rear tire I can see maybe 1-2 mm of side movement at the axle. I didn't put a dial indicator on it but as I no longer ride anywhere near the edge, I can't feel it so I am going to file it for future reference.

With the reservoir under the seat, (just as Glynn did), I found that I could not close the seat without removing the little "spare key tray" that rests in the frame in front of the fuse box. No problems.

First ride, the suspension felt more firm and "confident" than the previous stock suspension. No knocks or binding on any body panels which was a good start. Currently the bike is not registered for use on the road and I have to get a "Warrant of Fitness" before it is registered. Both jobs for next week and then I can have a ride through the local gorge.

Reading up on other forum experiences with the swing arm pivot bar rusting inside its sleeve, I am going to remove it and give it a through coating of grease just to make sure it doesn't seize up for the next owner. I had considered putting in a grease nipple into the frame in that area, but for the life of me I can't see how any grease could get into the sleeve unless holes or slots were cut out of it.

I am delighted with the feel of the new shock absorber. The ride felt far more "confident" - a bit like the change when you put new tyres on. It felt like a different bike. Immediately the bike was firmer, sat a little higher and the steering more positive into corners. I was getting more feedback from the road.

The new ride was a little harsh for me, so I adjusted the preload tension in the spring from 35mm of exposed thread down to 25mm of exposed thread. This made the ride more comfortable for around town riding. I am yet to do a trip out into the local gorge. Looking forward to it.

Long rides resulted in a sore backside and since I seldom have a passenger I have re-evaluted whether the TT600 spring is suitable. It isnt. The TT600 suspension works through a lever system. The TT600 spring is not progressive since the levers provide the progressive force. (I didn't give it a thought. Doh...)

The diameter of the TT600 springs and those of the XZ550 are the same. But the XZ550 spring is softer but quite a bit longer. I have had the XZ550 progressive spring cut down and squared off to the same length as the TT600, (Leaving the progressive end intact.)

Tonight I put the XZ550 cut down spring on to the TT600 shock absorber and tried a rear end static sag test. Yippee. 30mm with the tiniest bit of pre-tension on the shortened spring, - and about 50mm more pretension to play with on the shock absorber body. Hopefully next summers riding will be a whole lot more gentle on my arse and the handling will be vastly improved.

There have been several members who used shocks from linkage style suspensions with the same result you had. Your fix make perfect sense in that the spring designed for the bike is back in use. Glad it worked out and thanks for the update.

Logged

It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring. Carl Sagan

People will have you believe that the moment you cut a spring it is going to shatter and kill babies, if not yourself. I suspect the truth is somewhat less than that extreme.Regardless, It's certainly an illegal modification in NZ. It will make you fail a Warrant of Fitness - if they notice it.